Detection of JC virus infection in progressive multifocal leukoencephalopathy: the first documented case in Thailand.

Progressive Multifocal Leukoencephalopathy (PML) is a demyelinating brain disease caused by human polyoma JC virus (JCV). This disease is an important cause of morbidity and mortality in AIDS patients. Definite diagnosis currently requires a brain biopsy. PCR for JCV of CSF, an emerging diagnostic tool, has a high specificity for the diagnosis of PML in patients with characteristics on clinical and neuroradiological findings. The authors report a 36-year-old woman who presented with prolonged fever, progressive weakness, and slow speech for 2 months. Clinical features and MRI findings were compatible with PML. Qualitative PCR for JCV of CSF showed a positive result. This report emphasizes the yield of PCR, the CSF for JCV in a diagnosis of PML, which may reduce the need for a brain biopsy in such cases.